So, interestingly enough, I have found that this is not the best way to write what is being expressed here. The best way... Is Polish.
As for a "velarised L" in Polish, imagine the sound of l in "lady" to get an approximation of the sound. This kind of L used to be common in the eastern parts of Poland, but is now associated primarily with either older people from Warsaw, or a specific kind of old theatrical performances, where it is still used. Hilariously, I once thought a Czech guy who spoke some Polish was from Warsaw, until I realised no, he's just Czech and they don't have an equivalent for Ł
